Low-loss Self Forming Waveguide (SFWG) coupling of two different optical elements such as waveguides that are closely spaced can be accomplished with UV-photosensitive polymers irradiated with ultraviolet (UV) light. Coupling between two optical fibers or between a fiber and a glass waveguide can be accomplished by proper insertion of the photosensitive polymer between them, alignment of the optical waveguides and passage of UV through both of those waveguides. A methodology for forming such a SFWG for coupling two optical elements is described in Kung-Li Deng, et al., “Self-aligned Single-Mode Polymer Waveguide Interconnections for Efficient Chip-to-chip Optical Coupling”, IEEE Journal of Selected Topics in Quantum Electronics, Vol. 12, No. 5, September/October 2006, which is incorporated by reference herein in its entirety. In the Kung-Li reference, UV light is passed through both waveguides into the photosensitive polymer. Therefore, the prior art methodology relies on both waveguides being UV transmissive. It was believed that UV coming only from one waveguide would not be able to “find” the second waveguide without exceptional alignment, and that the resulting waveguide would spread, resulting in poor coupling. This two-sided UV passage methodology cannot be used to form a SFWG when one or both of the optical elements (e.g., waveguides) to be coupled is non-UV transmissive, e.g., not made of a UV transmitting material or otherwise incapable of supporting UV light transmission.
In view of the foregoing, there exists a need for improved approaches and methodologies for producing SFWGs suited for coupling optical elements where at least one of the optical elements is non-UV transmissive.